The present technique includes a case member of a body and a supporting mechanism. The case member of a body includes a holding compartment having a shaft support at one end of the holding compartment. The supporting mechanism is receivable in the holding compartment of the case member and holds a display monitor. The supporting mechanism includes a first supporting member and a second supporting member, the first supporting member having, at a first end, a pivoting portion pivotally supported on the shaft support of the holding compartment, and a shaft support at a second end, and the second supporting member having a pivoting portion pivotally supported on the shaft support of the first supporting member. The supporting mechanism is configured to move the shaft support of the first supporting member and the pivoting portion of the second supporting member in an extrusion direction from the holding compartment.